Conventionally, a testing machine is known in which right and left driving screws for elevating a crosshead are driven by the motor to elevate the crosshead to exert a test force on a test piece and the test piece is evaluated (for instance, see Patent Document 1). In this kind of testing machine, there is provided an automatic stop device in order to stop the crosshead at an arbitrary position. In, for instance, the testing machine described in Patent Document 1, a movable member is elastically supported on a side of a screw pole such that it can move in the longitudinal direction. Strikers are attached to the movable member such that their positions can be adjusted in the longitudinal direction. The movement of the movable member is detected by the position sensor. When the crosshead collides with the striker while the crosshead is elevating, the movable member is pushed and a signal indicating that the crosshead has reached the arbitrary position is output from the position sensor to automatically stop the crosshead. To return to the original state from the automatically stopped state, the striker is caused to become spaced apart from the crosshead to return the movable member to the original position.
Patent Document 1: Japanese Laid-Open Patent Application No. H09-292320